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authorAndres Salomon <dilinger@queued.net>2008-04-28 02:15:03 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2008-04-28 08:58:36 -0700
commitb6f448e99ce7955b9707ed36a46cab2c6ddf7ddc (patch)
tree74ae26692c1fd713a0178faca99dea6761d442e8
parent46fb6f110dfc3fc99f44cf701f66ea3e790b6a81 (diff)
downloadlinux-b6f448e99ce7955b9707ed36a46cab2c6ddf7ddc.tar.gz
PM/gxfb: add hook to PM console layer that allows disabling of suspend VT switch
Prior to suspend, we allocate and switch to a new VT; after suspend, we switch back to the original VT. This can be slow, and is completely unnecessary if the framebuffer we're using can restore video properly. This adds a hook that allows drivers to select whether or not to do this vt switch, and changes the gxfb driver to call this hook. It also adds a module param to gxfb to allow controlling of the vt switch (defaulting to no switch). (Note: I'm not convinced that console_sem is the best way to protect this, but we should probably have some form of locking..) [akpm@linux-foundation.org: build fix] Signed-off-by: Andres Salomon <dilinger@debian.org> Cc: Jordan Crouse <jordan.crouse@amd.com> Cc: "Antonino A. Daplas" <adaplas@pol.net> Cc: Pavel Machek <pavel@ucw.cz> Cc: "Rafael J. Wysocki" <rjw@sisk.pl> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
-rw-r--r--Documentation/fb/gxfb.txt3
-rw-r--r--drivers/video/geode/gxfb_core.c7
-rw-r--r--include/linux/suspend.h15
-rw-r--r--kernel/power/console.c27
4 files changed, 48 insertions, 4 deletions
diff --git a/Documentation/fb/gxfb.txt b/Documentation/fb/gxfb.txt
index b5609614201..2f640903bbb 100644
--- a/Documentation/fb/gxfb.txt
+++ b/Documentation/fb/gxfb.txt
@@ -45,7 +45,8 @@ Accepted options:
mode_option - specify the video mode. Of the form
<x>x<y>[-<bpp>][@<refresh>]
vram - size of video ram (normally auto-detected)
-
+vt_switch - enable vt switching during suspend/resume. The vt
+ switch is slow, but harmless.
--
Andres Salomon <dilinger@debian.org>
diff --git a/drivers/video/geode/gxfb_core.c b/drivers/video/geode/gxfb_core.c
index 151d964c025..f16c21d5bc2 100644
--- a/drivers/video/geode/gxfb_core.c
+++ b/drivers/video/geode/gxfb_core.c
@@ -29,6 +29,7 @@
#include <linux/delay.h>
#include <linux/fb.h>
#include <linux/console.h>
+#include <linux/suspend.h>
#include <linux/init.h>
#include <linux/pci.h>
#include <asm/geode.h>
@@ -37,6 +38,7 @@
static char *mode_option;
static int vram;
+static int vt_switch;
/* Modes relevant to the GX (taken from modedb.c) */
static const struct fb_videomode gx_modedb[] __initdata = {
@@ -382,6 +384,8 @@ static int __init gxfb_probe(struct pci_dev *pdev, const struct pci_device_id *i
gxfb_check_var(&info->var, info);
gxfb_set_par(info);
+ pm_set_vt_switch(vt_switch);
+
if (register_framebuffer(info) < 0) {
ret = -EINVAL;
goto err;
@@ -502,5 +506,8 @@ MODULE_PARM_DESC(mode_option, "video mode (<x>x<y>[-<bpp>][@<refr>])");
module_param(vram, int, 0);
MODULE_PARM_DESC(vram, "video memory size");
+module_param(vt_switch, int, 0);
+MODULE_PARM_DESC(vt_switch, "enable VT switch during suspend/resume");
+
MODULE_DESCRIPTION("Framebuffer driver for the AMD Geode GX");
MODULE_LICENSE("GPL");
diff --git a/include/linux/suspend.h b/include/linux/suspend.h
index 1d7d4c5797e..a6977423baf 100644
--- a/include/linux/suspend.h
+++ b/include/linux/suspend.h
@@ -12,11 +12,22 @@
#include <asm/errno.h>
#if defined(CONFIG_PM_SLEEP) && defined(CONFIG_VT) && defined(CONFIG_VT_CONSOLE)
+extern void pm_set_vt_switch(int);
extern int pm_prepare_console(void);
extern void pm_restore_console(void);
#else
-static inline int pm_prepare_console(void) { return 0; }
-static inline void pm_restore_console(void) {}
+static inline void pm_set_vt_switch(int do_switch)
+{
+}
+
+static inline int pm_prepare_console(void)
+{
+ return 0;
+}
+
+static inline void pm_restore_console(void)
+{
+}
#endif
typedef int __bitwise suspend_state_t;
diff --git a/kernel/power/console.c b/kernel/power/console.c
index 89bcf4973ee..b8628be2a46 100644
--- a/kernel/power/console.c
+++ b/kernel/power/console.c
@@ -7,17 +7,39 @@
#include <linux/vt_kern.h>
#include <linux/kbd_kern.h>
#include <linux/console.h>
+#include <linux/module.h>
#include "power.h"
#if defined(CONFIG_VT) && defined(CONFIG_VT_CONSOLE)
#define SUSPEND_CONSOLE (MAX_NR_CONSOLES-1)
static int orig_fgconsole, orig_kmsg;
+static int disable_vt_switch;
+
+/*
+ * Normally during a suspend, we allocate a new console and switch to it.
+ * When we resume, we switch back to the original console. This switch
+ * can be slow, so on systems where the framebuffer can handle restoration
+ * of video registers anyways, there's little point in doing the console
+ * switch. This function allows you to disable it by passing it '0'.
+ */
+void pm_set_vt_switch(int do_switch)
+{
+ acquire_console_sem();
+ disable_vt_switch = !do_switch;
+ release_console_sem();
+}
+EXPORT_SYMBOL(pm_set_vt_switch);
int pm_prepare_console(void)
{
acquire_console_sem();
+ if (disable_vt_switch) {
+ release_console_sem();
+ return 0;
+ }
+
orig_fgconsole = fg_console;
if (vc_allocate(SUSPEND_CONSOLE)) {
@@ -50,9 +72,12 @@ int pm_prepare_console(void)
void pm_restore_console(void)
{
acquire_console_sem();
+ if (disable_vt_switch) {
+ release_console_sem();
+ return;
+ }
set_console(orig_fgconsole);
release_console_sem();
kmsg_redirect = orig_kmsg;
- return;
}
#endif